JP-2001-263015A shows a driving apparatus which adjusts a control amount of the controlled member according to an axial position of the control axis member. The driving apparatus is slidably supported by a shaft which is different from a camshaft of a valve cam, and is provided with an intermediate driving mechanism which transfers a driving force of the valve cam to an intake valve and/or an exhaust valve. Thereby, a reciprocating motion of the control axis member is converted to a rotational motion, and a relative lift amount difference between the valve cam of the intermediate driving mechanism and the intake valve and/or the exhaust valve according to an axial position of the control axis member.
For instance, when the driving apparatus is adapted to adjust a valve lift of the internal combustion engine, the control axis member always receives a one-way load. On the other hand, in order to keep a predetermined valve lift amount at the starting of engine for example, it is desirable that the control axis member be positioned according to a predetermined valve lift amount. However, in order to keep the position of the driving cam at a constant position, it is necessary to constantly add a driving force from the driving power source to the camshaft driving the driving cam, or to provide a complicated mechanism such as an electromagnetic clutch.